Heating of fluids



y 1933- M. W. BARNES 1,908,103

HEATING OF FLUIDS Filed Nov. 8, 1930 been applied an Patented May 9, 1933 UNITED STATES PATENT OFFICE MARION W. BARNES, OF CHICAGO, ILLINOIS, ASSIGNOB TO UNIVERSAL OIL PRODUCTS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION'OF SOUTH DAKOTA HEATING OF FLUIDS v Application filed November 28, 1930. Serial No. 498,830.

This invention relates to improvements in heating fluids and refers particularl the improved method and means of e ciently utilizing the relatively high temperatures encountered in the combustion zone of a furnace to supply heat to fluid undergoing treatment.

The concepts of the present invention permit its use in heatin any fluid and the principles of the invention may be applied to any type of furnace. The embodiment herein described is, however, particularly adapted to the heating of hydrocarbor oils 1n either a liquid or vaporous state, or partially in both, to high temperatures such as those employed in cracking.

Briefly described, the invention comprises utilizin that portion or portions of a furnace w ere relativelyhot combustion gas and/or flame temperatures are encountered, to supply heat to the fluid undergoin treatment through a suitable protecting s eet or other barrier which may protect the fluid conduit from direct impingement of the flame and the destructive action of excessively hot combustion gases.

The attached diagrammatic drawing lllllS- trates one particular type of furnace, such as utilized in cracking hydrocarbon oils, to which the princi les of the invention have in conjunction with the following description will serve to more clearly illustrate the features of the invention. The invention is, however, not limited to the type of furnace shown in the drawin or to any other specific type of furnace. %lombustion'zo ne 1 of the furnace may be supplied with combustible materials through one or a plurality of tunnel structures 2 having firing compartment 3 and air ducts 4 and 5, re ulated respectively by dampers 6 and 7 ombustible mixtures such as, for example, fuel oil and steam may be supplied to firing tunnel 3 through burner 8. t is to be understood of course, that other types of fuel such as gas, pulverized solid fuel or the like, may be used.

Tubes 9 are disposed along the front wall 10 and roof 11 of the furnace and receive primarily radiant heat from the flame and gases in combustion zone 1 and the surrounding walls and floor 12 of the furnace. Tubes 13 located near the rear wall 14 of the furnace receive substantially convection or fluid heat from the combustion gases passing between the tubes to flue 1'3, and bridge wall 15 separates the combustion zone 1 from the convection heating chamber in which is located the bank of said convection tubes.

As an embodiment of one of the primary features of my invention, bridge wall 15 may be provided with a hollow portion 17 in which are disposed tubes 18. The back 19 of bridge wall 15 may preferably be constructed of fire brick or other suitable refractory material and the front 20 may be of any suitable material capable of transmitting radiant heat to tubes 18, such as nickel-chromium bearing alloys, silichrome steel, chrome-iron or other metals capable of withstanding the high temperatures encountered in the combustion zone, or non-metallic materials such as fire clay or carborundum shapes may be employed if desired. Perforated bafiie wall 21 may be provided directly in front of bridge wall 15 to break up the flame and prevent its direct impingement upon the front 20 of the bridge wall.

It is evident that in the case illustrated, the tubes 18, while protected from the destructive action of the flameand hot combustion gases in combustion zone 1, may derive the benefit of the hi h temperatures encountered in this zone fiy-being supplied with heat transmitted through and/or radiated from the front 20 of bridge wall 15. It will be understood that similar benefits may be derived by constructing other walls of the furnace such as front wall 10 and roof 11 with a hollow space similar to that provided at17 and with a protecting front similar to 20. Such embodiments are entirely within the scope of the present invention.

As another feature of the invention supporting beams 22 such as are ordinarily employed to support the tubes 13 of the convection bank may extend through bridge wall 15 and serve as supporting members for tubes 18, serving at the same time to reinforce and stifien bridge wall 15, permitting relativel light and inexpensive construction of t e bridge wall. The light construction of brid wall is also advantageous in coolin the urnace when its operation has been iscontinued as the ordinary massive brid e wall construction retains heat for a considerable period of time after the fires have been extinguished. This same feature also renders the improved furnace more responsive to changes in its firing.

As a specific example of the heating efficiency of that portion of the furnace wherein the features of the present invention are utilized, assuming a temperature of say 1950 F. in the combustion zone and a temperature of say 750 F. in the fluid passing through the bridge wall tubes, the theoretical rate of of heat transfer is in excess of 5,000 B. t. u. per square foot per hour.

It is apparent from the foregoing description that my invention can readily be used in steam boilers and, in general, any fluid heating furnaces.- Hence, I do not wish to be limited to the specific use described, nor the the specific example given.

I claim as my invention:

1. In combination, a furnace having a heating chamber and an exit passageway for flue gases,'a hollow bridge wall separating said heating chamber from said exit passageway, a plurality of tubes interposed in the space provided in the hollow bridge wall, a plurality of tubes disposed in said exit passageway, and common means for supporting the tubes in said hollow bridge wall and in said exit passageway.

2. In combination, a furnace having a heating chamber and an exit passageway for flue gases, a; hollow bridge wall separating said heating chamber from said exit passageway, a plurality of tubes interposed in the space rovided in the hollow bridge wall, a plurality of tubes disposed in said exit passageway, and common means for supporting the tubes in said hollow bridge wall and in said exit passageway comprising a pluralityof metallic beams transversely anchored in said hollow bridge wall.

In testimony whereof I aflix my signature MARION W. BARNES. 

